improve contrast of calendar events

package.json

@@ -19,6 +19,7 @@
         "@playwright/test": "^1.41.1",
         "@tailwindcss/forms": "^0.5.9",
         "@tailwindcss/typography": "^0.5.15",
+        "@types/chroma-js": "2.4.5",
         "@types/node": "^22.10.10",
         "@vitejs/plugin-vue": "^5.2.1",
         "@vue/tsconfig": "^0.5.1",
@@ -55,6 +56,7 @@
         "@vue/eslint-config-typescript": "^14.3.0",
         "@vueuse/core": "^12.8.2",
         "@vueuse/integrations": "^12.5.0",
+        "chroma-js": "3.1.2",
         "class-variance-authority": "^0.7.1",
         "clsx": "^2.1.1",
         "dayjs": "^1.11.11",